A magnetic tunnel junction unit and a spintronic device

Abstract

The invention discloses a tunnel junction unit and a magnetic random access memory, which comprises a first electrode, a first free layer, a non-magnetic insulating layer, a pinning layer and a second electrode connected in sequence, and also includes a connection between the first electrode and the first electrode. The second free layer between the free layers, the cross-sectional area of ​​the second free layer is smaller than the cross-sectional area of ​​the free layer; the second free layer and the first free layer together form a composite free layer structure; the second free layer is used for gathering current, so that the current density at the second free layer is greater than the current density at the first free layer, so that the magnetic moment of the second free layer is reversed before the first free layer; due to the difference between the second free layer and the first free layer The exchange coupling effect between them makes the reversal of the magnetic moment of the second free layer drive the reversal of the magnetic moment of the first free layer; the degree of magnetization reversal of the composite free layer in the magnetic tunnel junction unit is improved, and the reversal current density of the composite free layer is reduced. And under the same current density excitation condition, the TMR value of the magnetic tunnel junction unit is improved.

Description

technical field [0001] The invention belongs to the field of spin electronic devices, and more specifically relates to a tunnel junction unit and a magnetic random access memory. Background technique [0002] The rapid popularization of computer networks around the world makes the amount of data that people need to store, process and transmit grow exponentially, and the huge amount of data puts forward new requirements for storage technology. As one of the main information storage technologies, solid-state memory is mainly used in computer main memory and storage chips of various portable electronic products. In recent years, its market growth rate is much higher than that of other storage devices such as hard drives. , fast read and write speed, low power consumption, and low noise solid-state hard drives are sought after, and solid-state memory will have a broader market prospect. [0003] The solid-state memory chips currently used for computer main memory are mainly dyn...

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Problems solved by technology

[0008] Aiming at the improvement requirements of the prior art, the present invention provides a magnetic tunnel junction unit, the purpose of which is to effectively reduce the magnetization switching current density and improve the degree of magnetization switching of the free layer, thereby solving the problem that the existing magnetic tunnel junction unit has no Make full use of the flipping effect of spin electrons on the magnetic moment of the free layer, and do not make full use of the weakening effect of Joule heat on the magnetic anisotropy strength during the flipping process of the free layer, resulting in the inability to sufficiently reduce the flipping current density and improve the TMR of the MTJ memory cell value technical issues

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